Pump-multiple piece bushing



1950 J. A. LAUCK ETAL MP-mm YM BUSHING fnvenforts' Patented Oct. 31,1950- r 2,527,941

UNITED STATES PATENT'OFFICE 2,527,941 PUMP-MULTIPLE PIECE BUSHING JohnA. Lauck, Shaker Heights, and James A. Compton, South Euclid, Ohio,assignors to Borg-Warner Corporation, Chicago, 111., a cornotation ofIllinois Application May 22, 1948, Serial No. 28,646

11 Claims. (Cl. 103-126) 2 The present invention relates to gear ypeprovided a novel and improved bushing construcliquid pressure generatorsor pumps having beartion. comprising a bearing and pumping seal deingand pumping seal defining bushing means fining assembly indicatedgenerally at B and it embracing the axially extending gear journals. isto this novel arrangement in combination that It is an object of thepresent invention to pro- 5 the present invention is particularlydirected. vide an improved arrangement 01 gear pump in- This inventionpresents an improvement over corporating bearing and pumping sealdefining the earlier construction disclosed and claimed in bushingsincluding radially extending inner Roth and Lauck Patent No. 2,420,622.flanges and axially outwardly extending tubular In the broader aspectsof the present invenportions, furnishing the flexibility, particularlytion this pumping seal and bearing defining bushimportant in pumps ofrelatively large volumetric ing assembly comprises a plurality ofaxially disdisplacement. posed parts Bi and B! so arranged as to pro- Itis a more specific object to provide an arvide the flexibility that isrequired particularly rangement oi this type wherein the bushing asingear pumps of the present type having a relasembly is composed 01' aplurality of parts makll tively large volumetric displacement.

ing it possible for the bearing surface areas to In the more specificaspects of our invention have a limited angular relative movement inorder assembly B comprises a first annular ring shaped to provideflexibility. member having an inner surface sealing area II It is stillanother object to provide an arrangeextending from a position below theroots of the ment of the present type incorporating a space U gear teethradially outwardly coextensive with between the opposed bushing elementsdefining said teeth, said inner surface ling area I. bea pressurechamber for the reception or the presing eilective to engage theadjacent gear side face sure liquid acting to hold the inner bushingmemin iquid Pumping seal relation. Annular member in liquid pumping sealengagement with the her BI is further provided with an allycorrespondlng gear side face. tending cylindrical ufl portion 2| adap edin Other objects, advantages and uses of my inles i a y op rate with acomplementary vention will become apparent from a reading of surfaceportion of the second annular ringshaped Fig. 1 is an elevation viewpartially in cross nal "team! it will be noted that this surface hassection along l-l of Fig 2 and showing a prea relatively small axialdimension and has a ferred embodiment oi the invention; slightly greaterinside diameter than the outside Fig. 2 is a cross sectional view takensubstandiameter 01' h cia d J urnal. This is imtlally on the line 2 ofFig. 1; and po -tent ce h me w l h s mit 1' a ry Fig, 3 1 a considerablyenlarged broken away limited but nevertheless essential angularmovecross sectional view corresponding to a portion ment between thebearing f e lied of Fig. 1 and bringing out to particular advanby theexternal periphery 01' Journal l'la and tage the novel construction andarrangement of sealing surface 2|! of annular member Bl northe bushingand bearing amembly iorming the 40 mally extending at right angles tothe axis of said Journal. particularly directed. For the purpose ofproperly venting the radial Referrin now in greater detail to thefigures inner terminal of sealing surface 20 to the rear of the drawing.a gear pump indicated generof annular member Bl there is provided by thean at It includes a primar housing section II difl'erence in insidediameter of the suri'ace I2 and a closure section Ho. Fluid inlet [2 andfluid and the outside diameter 01 the associated Jour- IB. Received inthese chambers are a pair of important as the volumetric displacement01' a intermeshing gears I 6 and II formed with axially pump of thistype is increased.

oppositely extended journals lIo, lib, Ho and As the axial dimension ofbearing surface 22 "b. was reduced experimentally in an effort to main-Peri'orming the very important function of tain the requisite alignmentbetween all sealing the radially extending gear side faces surfaces theroblem of continuing to supply the on the left hand side thereof in Fig.1, we have requisite pressure to the rear surface oi the bushing for thepurpose of pressure loading the same was likewise made more difiicult.

The second annular ring shaped member B2 is given a greater axialdimension than that of the first annular member Bi. Cylindrical bearingsurface 28 thus embraces journal Ila for a considerable portion of theaxial extent thereof amounting to several times the axial dimension ofbearing surface 22 of annular member Bl, the importance of whicharrangement will be made to appear. External cylindrical surface 21 ofannular member B2 is complementary to and is received telescopicallywithin cylindrical surface 2! o! annular ring Bl. Flexible donut sealring 2! is interposed between annular ring members BI and B2.

For the purpose of normally maintaining an initial pumping sealengagement there are provided a plurality of symmetrically andcircumferentially disposed coil compression springs 29 one terminal ofeach of which engages the closed end of a cylindrical bore 30 formed inannular ring portion B2, while the other terminal engages a rear surface200 of the first annular ring member Bl. The two annular ring portionsBi and B2 are thus normally spaced apart in the area of the above coilcompression springs to thus define a motive pressure chamber M providingfor the action of pressure liquid generated by the gears l6 and I1acting on rear surface 201; of the first named annular ring member Biand eifective to cause the inner surface 2|! to be urged into liquidpumping seal relation with the corresponding side face of gear l1, aswill appear.

Axially extending groove 3| is formed on the inner periphery of thesecond annular ring member B2 but it will be noted that the same doesnot extend completely to the left hand terminal of the annular ring,looking at Fig. 3. The internal bearing surface 26 is uninterrupted inthe area designated 26a. Due to the manufacturing tolerances present inthe area 26a, there will not be a complete seal but merely a small dropin the value of the pressure existing in axially extending groove 3! andthe left hand terminal of axially extending bearing surface 26a incommunication with the atmospheric pressure. This arrangement has beenprovided since it has been found that a better operation is realizedwhere a small drop in pressure is present as distinguished from ventingaxially extending groove 3| directly to the atmospheric In Fig. 1, oneventing groove Si is shown as formed in the upper, inner side of upperbushing member B2 and in the upper inner side of the corresponding lowerbushing member. The peripheral location of these venting grooves,however, is largely a matter of choice, since the grooves communicate attheir inner ends with the annular chamber or groove 23 and at theirouter ends with the leakage path at the inner bushing surface 215a. Eachgroove 3| is made approximately equal in depth to the depth of theannular passage 23, while the width of the groove is selected to providethe requisite ventin: action;

The output pressure delivered by gears 16 and I! may be communicated tomotive chamber M in any desired manner; however a preferred arrangementeffective to accomplish this is disclosed in the above referred toearlier patent and includes the provision of a passage 32 leading fromthe area of juncture between the upper and lower one of the first namedannular ring members Bi to a point in the rear thereof in communicationwith surface 20a. As in the disclosure of the above patent the oppositecorresponding juncture between the upper and lower annular bushing ringsBI is closed by a closure plug 33 indicated in dotted lines andfunctioning to prevent the recirculation of the pressure liquid back tothe inlet side of the gears.

There is of course provided in addition to the above, the necessarymaining elements not forming a special aspect of the present inventionbut required to complete the structure. Lubricating grooves 34 areformed in the faces 28 of annular bushing rings Bi for a portion only ofthe circumferential extent thereof. In addition anti-trapping recess 35is likewise provided. Coupling connector He is formed as an extension ofupper journal "a for the purpose of connecting the gears to a suitablesource of power, such as a geared connection with an aircraft engine.Fastening means lib, in the form of cap screws, function to attachclosure section Ha to primary section II of the housing.

Whfle the present invention has been disclosed in connection with aspecific embodiment thereof it is to be understood that this is by wayof example rather than limitation and the invention is to be defined bythe appended claims which should be accorded a scope commensurate withthe prior art.

What is claimed is:

1. In an inter-meshin gear type pump having bearing and pumping sealdefining bushing means embracing axially extending gear journals andsealably en agin the corresponding gear teeth side faces, said journalsextending axially said bushing having an inner radially extendingpumping seal defining surface area adapted to engage the correspondinggear side face and having a first internal cylindrical journal bearingarea; a second axially outwardly disposed annular ring memher, saidsecond annular ring having one surface thereof spaced from the adjacentsurface of said first annular ring to thus define a liquid pressuremotive chamber therebetween, said second annular ring member having asecond internal cylindrical journal bearing area therein, said first andsaid second journal bearing areas providing for limited angular movementbetween the plane of said pumping seal defining surfaces and the axis ofthe corresponding journal.

2. In an intermeshing gear type pump having bearing and pumping sealdefining bushing means embracing an axially extending gear journalfunctioning to provide a bearing for said journal and a pumping sealwith the adiacent gear side face, said bushing means comprising a firstannular ring shaped member having an inner surface sealing areaextending from a position below the roots of the gear teeth radiallyoutwardly coextensive with said teeth, said inner surface sealing areabeing effective to engage the adjacent gear side face in liquid pumpingseal relation; a second annular ring shaped member having a greateraxial dimension than that of said first annular member; said first andsaid second annular members being formed with complementary telescopingportions, an annular liquid sealing ring positioned between saidtelescoping portions. said first annular member being formed with asecond generally radially extending surface area facing axiallyoutwardly from said gear and adapted to be responsive to liquid pressuregenerated by said pump for holding said first inner surface area inpumping seal engagement with the corresponding gear side face, saidsecond surface area being spaced from the opposed surface of said secondannular memher to thus provide with the surrounding housing wall, amotive chamber for the liquid pressure to act on said second surfacearea, spring means between said first and said second annular memberseffective to insure an initial pumping seal, and means effective todeliver liquid pressure generated by said gears to said motive chamber.

3. In an intermeshing gear type pump having bearing and pumping sealdefining bushing means embracing an axially extending gear Journal inbearing relation thereto and also sealably engaging the correspondinggear side face, said bushing means comprising a first annular shapedring member having a first inner radially extending surface areaefifective to engage the corresponding opposed gear side face in pumpingseal relation, said first annular ring shaped member having a firstinternal cylindrical journal bearing area, and having a steppedcountersunk enlarged bore on the outer portion thereof comprising afirst countersunk portion and a second enlarged countersunk portion; asecond axially outwardly spaced annular ring shaped member, said secondannular ring member having a reduced cylindrical portion complementaryin size to the first one of said stepped countersunk portions in saidfirst annular member and received in telescoped relation thereto, aflexible-o-ring seal received within the larger one of said countersunkportions and sealably engaging said reduced cylindrical portion of saidsecond annular ring member, coil compression spring means interposedbetween said first and said second annular ring members effective tomaintain said first surface area in initial sealing contact with saidgear side face, said first and said second annular members thus beingseparated to define therebetween an annular liquid pressure receivingmotive chamber, and means effective to deliver liquid pressure generatedby said gears to said motive chamber, said second annular ring memberbeing further characterized by the provision of a second internalcylindrical journal bearing area, said second cylindrical bearing areahaving an axial dimension several times the value of the axial dimensionof said first internal cylindrical Journal bearing area.

4. In an intermeshing gear type pump having bearing and pumping sealdefining bushing means embracing an axially extending gear journal inbearing relation thereto and also sealably engaging the correspondinggear side face, said bushing means comprising a first annular shapedring member having a first inner radially extending surface areaefiective to engage the corresponding opposed gear side face in pumpingseal 'relation, said first annular ring shaped member having a firstinternal cylindrical journal bearing area, and having a steppedcountersunk enlarged bore on the outer portion thereof comprising afirst countersunk portion and a second enlarged countersunk portion; asecond axially outwardly spaced annular ring shaped member, said secondannular ring member having a reduced cylindrical portion complementaryin size to the first one of said stepped countersunk portions in saidfirst annular mem-" 6 ber and received in telescoped relation thereto, afiexible-o-ring seal received within the larger one of said countersunkportions and sealably engaging said reduced cylindrical portion of saidsecond annular ring member, coil compression spring means interposedbetween said first and said second annular ring members effective tomaintain said first surface area in initial sealing contact with saidgear side face, said first and said second annular members thus beingseparated to define therebetween an annular liquid pressure receivingmotive chamber, and means efiective to deliver liquid pressure generatedby said gears to said motive chamber, said second annular ring memberbeing further characterized by the provision of a second internalcylindrical journal bearing area, said second cylindrical bearing areahaving an axial dimension several times the value of the axial dimensionof said first internal cylindrical journal bearing area, said firstnamed annular member being further characterized by the provision of anaxially extending annular passage formed between the inside diameter ofthe first annular ring member and the periphery of the journal and saidsecond named annular ring member being further characterized by theprovision of an axially extending relief groove formed in said secondcylindrical bearing surface, said relief groove terminating axiallyshort of the outer terminal of said second cylindrical bearing surfacearea.

5. An intermeshing gear type pump having bearing and pumping sealdefining bushing means embracing axially extending gear journals andsealably engaging the corresponding gear teeth side faces, said bushingmeans being formed in a plurality of axially disposed, par tiallyoverlapping parts, said gear Journals extending axially through saidbushing means, and means disposed between at least two of said parts forurging said parts axially apart, said plurallty of bushing parts beingeffective to permi limited flexibility of alignment between the portionof said bushing means engaging the gear teeth side faces and the portionof said bushing means embracing the gear journals.

6. An intermeshing gear type pump havim bearing and pumping sealdefining bushing means embracing axially extending gear JOlll nals andsealably engaging the corresponding gear teeth side faces, said bushingmeans balm formed in a plurality of substantially concentr c. partiallyoverlapping parts, said gear journals extending axially through saidbushing means. and means disposed between at least two of said parts forurging said parts axially apart, said plurality of bushing parts beingeflective to permit limited flexibility of alignment between the portionof said bushing means engaging the gear teeth side faces and the portionof said bushing means embracing the gear journals.

I. An intermeshing gear type pump having bearing and pumping sealdefining bushing means embracing axially extending gear jnur nals andsealably enga in the corresponding gear teeth side faces, said bushingmeans being formed in a plurality of substantially concentric, partiallyoverlapping parts, said gear iour nals extending axially through saidbushing means and means disposed between at least two of said parts forurging said parts axially apart. said plurality of bushing parts beingefi'eciire to permit limited flexibility of alignment between theportion of said bushing means engaging the gear teeth side faces and theportion of said bushing means embracing the gear journals, at least oneof said parts sealably engaging the corresponding gear side faces andanother of said parts embracing the axially extending gear journals inbearing relation.

8. An lntermeshing gear type pump having one set of pressure loadable,axially movable bearing and pumping seal defining bushing meansembracing axially extending gear journals, said bushing means havingpressure responsive motive surfaces adapted in response to applicationof pressure thereto to cause said bushing means to sealably engage thecorresponding gear side faces, a first pressure responsive surface areaon the side of said bushing means adapted to engage the gear side faces,a second pressure responsive area constituting the motive surfaces onthe side of said bushing means away from said gear side faces, a reliefrecess formed adjacent the inner periphery of said first pressureresponsive surface, and restricted passage means for venting said reliefarea to inlet pressure in such manner as to provide a smaller pressuredrop than would be afforded were the passage not restricted.

9. An intermeshing gear type pump having one set of pressure loadable,axially movahle bearing and pumping seal defining bushing meansembracing axially extending gear journals, said bushing means havingpressure responsive motive surfaces provided thereon adapted in responseto application of pressure thereto to cause said bushing means tosealably engage the corresponding gear side faces, a first pressureresponsive surface area on the side of said bushing means adapted toengage the gear side faces, a second pressure responsive areaconstituting the motive surfaces on the side of said bushing means awayfrom said gear side faces, a relief recess formed adjacent the innerperiphery of said first pressure responsive surface, and means defininga passage for venting said relief area to inlet pressure, said passagebeing restricted, at least in part, to reduce the pressure drop.

10. In an intermeshing gear type pump having bearing and pumping sealdefining bushing means embracing axially extending gear journals andseaiably engaging the corresponding gear teeth side faces, said gearjournals extending through said bushing means and said bushing meansbeing particularly characterized by being formed in a plurality ofaxially disposed parts, means disposed between at least two of saidparts for urging said parts apart, said plurality of bushing partspermitting limited flexibility of alignment between the gear Journalengaging portion of said bushing means and the portion of said bushingmeans sealably engaging the gear teeth side faces.

11. In an intermeshing gear type pump having one set of pressureloadable, axially movable bearing and pumping seal defining bushingmeans embracing axially extending gear journals, said bushing meanshaving pressure responsive motive surfaces provided thereon adapted inresponse to application of pressure thereto to cause said bushing meansto sealably engage the corresponding gear side faces, the gear Journalbearing surfaces of said bushing means having axially extending reliefgrooves formed therein, said grooves communicating at their inner endswith the gear side faces and terminating at their outer ends and axiallyshort of the outer terminal of said bushing, and means disposed betweenthe outer terminals of said bushing means having a slightly greaterinternal diameter than the outer diameter of the embraced portions ofsaid gear journals to provide passages to the outer ends of said bushingmeans of substantially smaller volumetric capacity than that of theassociated grooves.

JOHN A. LAUCK. JAMES A. COMPTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,285,819 Smith Nov. 26, 19181,372,576 Tullmann Mar. 22, 1921 1,379,587 Fisher May 24, 1921 1,597,411Kinney Aug. 24, 1926 1,644,817 Conant et a1 Oct. 11, 1927 2,391,072 PughDec. 18, 1945 2,420,622 Roth et a1 May 13, 1947 FOREIGN PATENTS NumberCountry Date 358,843 Great Britain Oct. 15, 1931

